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Friedhelm Hummel

Friedhelm Hummel
Swiss Federal Institute of Technology (EPFL) · Defitech Chair of Clinical Neuroengineering

Prof. Dr. med.

About

257
Publications
44,749
Reads
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17,731
Citations
Citations since 2016
107 Research Items
10901 Citations
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Additional affiliations
December 2016 - present
Hôpitaux Universitaires de Genève
Position
  • Professor (Associate)
September 2016 - present
Swiss Federal Institute of Technology / ETH Lausanne (EPFL)
Position
  • Chair
August 2013 - present
Favoloro University, Buenos Aires, Argentina
Position
  • Guest Professor

Publications

Publications (257)
Article
Full-text available
Introduction The WHO estimates that each year 5 million people are left permanently disabled after stroke. Adjuvant treatments to promote the effects of rehabilitation are urgently needed. Cortical excitability and neuroplasticity can be enhanced by non-invasive brain stimulation but evidence from sufficiently powered, randomized controlled multi-c...
Preprint
Full-text available
Reinforcement feedback can improve motor learning, but the underlying brain mechanisms remain unexplored. Especially, the causal contribution of specific patterns of oscillatory activity within the human striatum is unknown. To address this question, we exploited an innovative, non-invasive deep brain stimulation technique called transcranial tempo...
Article
Task-specific training constitutes a core element for evidence-based rehabilitation strategies targeted at improving upper extremity activity after stroke. Its combination with additional treatment strategies and neurotechnology-based solutions could further improve patients' outcomes. Here, we studied the effect of gamified robot-assisted upper li...
Preprint
The stimulation of deep brain structures has thus far been possible only with invasive methods. Transcranial electrical temporal interference stimulation (tTIS) is a novel, noninvasive technology that might overcome this limitation. The initial proof-of-concept was obtained through modeling, physics experiments and rodent models. Here, we show for...
Article
Full-text available
Enhanced behavioral interventions are gaining increasing interest as innovative treatment strategies for major depressive disorder (MDD). In this study protocol, we propose to examine the synergistic effects of a self-administered home-treatment, encompassing transcranial direct current stimulation (tDCS) along with a video game based training of a...
Article
Full-text available
Despite recent improvements, complete motor recovery occurs in <15% of stroke patients. To improve the therapeutic outcomes, there is a strong need to tailor treatments to each individual patient. However, there is a lack of knowledge concerning the precise neuronal mechanisms underlying the degree and course of motor recovery and its individual di...
Preprint
Full-text available
The neuronal processes sustaining motor recovery after stroke are still largely unknown. Cortical excitation/inhibition dynamics have been suggested previously as a key mechanism occurring after a stroke. Their supportive or maladaptive role immediately after a stroke and during the process of recovery are still not completely understood; it is hyp...
Article
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Introduction The DiSCoVeR trial is a multi-site, double-blind, sham controlled, randomized controlled trial (RCT) investigating the feasibility and efficacy of an innovative, self-applied treatment approach for patients suffering from major depressive disorder (MDD). The treatment approach incorporates non-invasive brain stimulation, i.e. prefronta...
Article
Practicing a previously unknown motor sequence often leads to the consolidation of motor chunks, which enable its accurate execution at increasing speeds. Recent imaging studies suggest the function of these structures to be more related to the encoding, storage, and retrieval of sequences rather than their sole execution. We found that optimal mot...
Article
Full-text available
Background: Healthy older adults show a decrease in motor performance and motor learning capacity as well as in working memory (WM) performance. WM has been suggested to be involved in motor learning processes, such as sequence learning. Correlational evidence has shown the involvement of the frontoparietal network (FPN), a network underlying WM p...
Article
Full-text available
Effective, patient-tailored rehabilitation to restore upper-limb motor function in severely impaired stroke patients is still missing. If suitably combined and administered in a personalized fashion, neurotechnologies offer a large potential to assist rehabilitative therapies to enhance individual treatment effects. AVANCER (clinicaltrials.gov NCT0...
Article
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Quantitative magnetic resonance imaging (qMRI) can increase the specificity and sensitivity of conventional weighted MRI to underlying pathology by comparing meaningful physical or chemical parameters, measured in physical units, with normative values acquired in a healthy population. This study focuses on multi-echo T2 relaxometry, a qMRI techniqu...
Article
Tractography enables identifying and evaluating the healthy and diseased brain's white matter pathways from diffusion-weighted magnetic resonance imaging data. As previous evaluation studies have reported significant false-positive estimation biases, recent microstructure-informed tractography algorithms have been introduced to improve the trade-of...
Preprint
Full-text available
Background Most studies on stroke have been designed to examine one deficit in isolation, yet survivors often have multiple deficits in different domains. While the mechanisms underlying multiple-domain deficits remain poorly understood, network-theoretical methods may open new avenues of understanding. Methods 50 subacute stroke patients (7±3days...
Preprint
Despite recent improvements, complete motor recovery occurs in less than 15% of stroke patients. To improve the therapeutic outcomes, there is a strong need to tailor treatments to each individual patient. However, there is a lack of knowledge concerning the precise neuronal mechanisms underlying the degree and course of motor recovery and its indi...
Preprint
Cortico-cortical paired associative stimulation (ccPAS), which repeatedly pairs single pulse TMS over two distant brain regions with a specific time interval, is thought to modulate synaptic plasticity. Applied to the motion cortical pathway, ccPAS has been shown to improve motion discrimination when specifically targeting backward projections, sti...
Article
Full-text available
Objectives (i) to create a shortened version of the Action Research Arm Test scale, (ii) to investigate its psychometric properties compared to the original scale and (iii) to externally validate it within an independent cohort. Design Prospective longitudinal cohort study. Settings Two University Hospitals (France, Switzerland). Participants 47...
Article
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Movements establish intended outcomes in the environment. To set these goals of movement, a plethora of brain process, often termed ‘cognition’, spell out the intended course of action. Articles investigating whether and when cognitive and motor functions may interact, and which brain regions may be responsible for their integration, are featured i...
Article
Mitochondrial health is based on a delicate balance of specific mitochondrial functions (e.g. metabolism, signaling, dynamics) that are impaired in neurodegenerative diseases. Rescuing mitochondrial function by selectively targeting mitochondrial stressors, such as reactive oxygen species, inflammation or proteotoxic insults (“bottom-up” approaches...
Article
Full-text available
Background: Latencies of motor evoked potentials (MEP) can provide insights into the motor neuronal pathways activated by transcranial magnetic stimulation (TMS). Notwithstanding its clinical relevance, accurate, unbiased methods to automatize latency detection are still missing. Objective: We present a novel open-source algorithm suitable for M...
Preprint
Full-text available
Introduction Understanding the causal relationship between a focal lesion and brain network (re)organization is a crucial step in order to accurately predict the resulting symptoms of the lesion and implement personalized rehabilitation strategies. Transcranial magnetic stimulation (TMS) can be used to create local and transient neural perturbation...
Preprint
Full-text available
Background Healthy older adults show a decrease in motor learning capacity as well as in working memory (WM) performance. WM has been suggested to be involved in motor learning processes, such as sequence learning. Correlational evidence has shown the involvement of the fronto-parietal network (FPN), a network underlying WM processes, in motor sequ...
Article
Full-text available
Interhemispheric interactions demonstrate a crucial role for directing bimanual movement control. In humans, a well-established paired-pulse transcranial magnetic stimulation paradigm enables to assess these interactions by means of interhemispheric inhibition (IHI). Previous studies have examined changes in IHI from the active to the resting prima...
Article
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Oscillatory activity in the cerebellum and linked networks is an important aspect of neuronal processing and functional implementation of behavior. So far, it was challenging to quantify and study cerebellar oscillatory signatures in human neuroscience due to the constraints of non-invasive cerebellar electrophysiological recording and intervention...
Preprint
Full-text available
During learning of novel motor sequences, practice leads to the consolidation of hierarchical structures, namely motor chunks, facilitating the accurate execution of sequences at increasing speeds. Recent studies show that such hierarchical structures are largely represented upstream of the primary motor cortex in the motor network, suggesting thei...
Article
Discrimination and integration of motion direction requires the interplay of multiple brain areas. Theoretical accounts of perception suggest that stimulus-related (i.e., exogenous) and decision-related (i.e., endogenous) factors affect distributed neuronal processing at different levels of the visual hierarchy. To test these predictions, we measur...
Article
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In summary, ML has great potential to leverage large amounts of data to support medical practitioners by making predictions of patients’ responses to treatments. However, it is important not to get swept up in the hype surrounding ML, and to realize that if used without sufficient care, it is likely to lead researchers into serious error by proposi...
Article
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Besides relying heavily on sensory and reinforcement feedback, motor skill learning may also depend on the level of motivation experienced during training. Yet, how motivation by reward modulates motor learning remains unclear. In 90 healthy subjects, we investigated the net effect of motivation by reward on motor learning while controlling for the...
Article
Full-text available
Stroke patients vary considerably in terms of outcomes: some patients present 'natural' recovery proportional to their initial impairment (fitters), while others do not (non-fitters). Thus, a key challenge in stroke rehabilitation is to identify individual recovery potential to make personalized decisions for neuro-rehabilitation, obviating the 'on...
Article
Visual motion discrimination involves reciprocal interactions in the alpha band between the primary visual cortex (V1) and mediotemporal areas (V5/MT). We investigated whether modulating alpha phase synchronization using individualized multisite transcranial alternating current stimulation (tACS) over V5 and V1 regions would improve motion discrimi...
Article
Background and purpose: Structural brain networks possess a few hubs, which are not only highly connected to the rest of the brain but are also highly connected to each other. These hubs, which form a rich-club, play a central role in global brain organization. To investigate whether the concept of rich-club sheds new light on poststroke recovery,...
Preprint
Full-text available
Besides relying heavily on sensory and reinforcement feedback, motor skill learning may also depend on the level of motivation experienced during training. Yet, how motivation by reward modulates motor learning remains unclear. In 90 healthy subjects, we investigated the net effect of motivation by reward on motor learning while controlling for the...
Article
Full-text available
The past decade has brought tremendous progress in diagnostic and therapeutic options for cerebrovascular diseases as exemplified by the advent of thrombectomy in ischemic stroke, benefitting a steeply increasing number of stroke patients and potentially paving the way for a renaissance of neuroprotectants. Progress in basic science has been equall...
Article
Full-text available
Transcranial direct current stimulation (tDCS)-based interventions for augmenting motor learning are gaining interest in systems neuroscience and clinical research. Current approaches focus largely on monofocal motorcortical stimulation. Innovative stimulation protocols, accounting for motor learning related brain network interactions also, may fur...
Article
Full-text available
While there is evidence that sensory processing and multisensory integration change with age, links between these alterations and their relation to cognitive status remain unclear. In this study, we assessed sensory thresholds and performance of healthy younger and older adults in a visuotactile delayed match-to-sample task. Using Bayesian structur...
Preprint
Visual motion discrimination involves reciprocal interactions in the alpha band between the primary visual cortex (V1) and the mediotemporal area (V5/MT). We investigated whether modulating alpha phase synchronization using individualized multisite transcranial alternating current stimulation (tACS) over V5 and V1 regions would improve motion discr...
Article
Full-text available
Objective: The relationship between white matter integrity and the brain-derived neurotrophic factor (BDNF) genotype and its effects on motor recovery after stroke are poorly understood. We investigated the values of fractional anisotropy (FA) in the corticospinal tract (CST), the intrahemispheric connection from the primary motor cortex to the ve...
Article
Introduction: Cognitive impairments are one of the most common remaining symptoms after a stroke. The use of neurotechnologies to enhance cognitive performance is a rapidly emerging field with encouraging results. Areas covered: Here, the authors empirically review the respective literature and critically discuss the technologies that are curren...
Article
Full-text available
The development of novel strategies to augment motor training success is of great interest for healthy persons and neurological patients. A promising approach is the combination of training with transcranial electric stimulation. However, limited reproducibility and varying effect sizes make further protocol optimization necessary. We tested the ef...
Preprint
Full-text available
Aging is characterized by changes in sensory and cognitive abilities. While there is evidence that decline in sensory acuity and enhanced multisensory integration predict cognitive status in healthy older adults, potential mechanistic links between these age-related alterations remain unclear. In the current study, we assessed performance of younge...
Article
Full-text available
Background: An increasing lifespan and the resulting change in our expectations of later life stages are dependent on a good health state. This emphasizes the importance of the development of strategies to further strengthen healthy aging. One important aspect of good health in later life stages is sustained skilled motor function. Objective: Here,...
Article
Full-text available
One of the pivotal challenges of aging is to maintain independence in the activities of daily life. In order to adapt to changes in the environment, it is crucial to continuously process and accurately combine simultaneous input from different sensory systems, i.e., crossmodal or multisensory integration. With aging, performance decreases in multip...
Article
Full-text available
A group of European experts reappraised the guidelines on the therapeutic efficacy of repetitive transcranial magnetic stimulation (rTMS) previously published in 2014 [Lefaucheur et al., Clin Neurophysiol 2014;125:2150-206]. These updated recommendations take into account all rTMS publications, including data prior to 2014, as well as currently rev...
Article
Stroke is one of the leading causes of long-term disability. Advanced technological solutions ("neurotechnologies") exploiting robotic systems and electrodes that stimulate the nervous system can increase the efficacy of stroke rehabilitation. Recent studies on these approaches have shown promising results. However, a paradigm shift in the developm...
Article
Stroke has become one of the main causes of visual impairment, with more than 15 million incidences of first-time strokes, per year, worldwide. One-third of stroke survivors exhibit visual impairment, and most of them will not fully recover. Some recovery is possible, but this usually happens in the first few weeks after a stroke. Most of the rehab...